用户指南和参考

ST_AsBinary

ST_AsBinary 接受几何图形对象并返回它的公认二进制表示。

语法

db2gse.ST_AsBinary(g db2gse.ST_Geometry)

返回类型

BLOB(1m)

示例

以下代码段说明 ST_AsBinary 函数如何将 BUILDINGFOOTPRINTS 表的占地形状复合多边形转换为 WKB 复合多边形。这些复合多边形被传递给应用程序的 draw_polygon 函数进行显示。

/* Create the SQL expression. */
strcpy(sqlstmt, "select db2gse.ST_AsBinary (footprint) from BUILDINGFOOTPRINTS
where db2gse.EnvelopesIntersect(footprint, db2gse.ST_PolyFromWKB(cast(? as blob(1m)),
db2gse.coordref()..srid(0)))");
 
/* Prepare the SQL statement. */
SQLPrepare(hstmt, (UCHAR *)sqlstmt, SQL_NTS);
 
/* Set the pcbvalue1 length of the shape. */
pcbvalue1 = blob_len;
 
/* Bind the shape parameter */
SQLBindParameter (hstmt, 1, SQL_PARAM_INPUT, SQL_C_BINARY, SQL_BLOB, blob_len,
0, shape, blob_len, &pcbvalue1);
 
/* Execute the query */
rc = SQLExecute (hstmt);
 
/* Assign the results of the query (the Zone polygons) to the
  fetched_binary variable.
 */
SQLBindCol (hstmt, 1, SQL_C_Binary, fetched_binary, 100000, &ind_blob);
 
/* Fetch each polygon within the display window and display it. */
while(SQL_SUCCESS == (rc = SQLFetch(hstmt)))
  draw_polygon(fetched_binary);
  


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